The long term objective of this project is to develop a prototype neurally-controlled prosthetic arm for use by upper-arm amputees. The arm will be controlled using command signals from motor nerves in the amputee's stump with tactile and positional feedback provided through the stimulation of sensory fibers in the nerve stumps to elicit natural perceptions of touch and proprioception. The aim is to provide for smooth, dexterous control of functions such as graded pinch grasp, wrist rotation, and elbow flexion/extension in an artificial arm that is well integrated into the patient's body image. The neural interface will use electrodes that can selectively record from and activate restricted subsets of neurons when implanted in peripheral nerves. Recording motor neuron activity from nerves in an amputee's stump will provide command signals that are both volitional and appropriate for control of the prosthetic limb. Stimulation of sensory axons will provide perceptual feedback about arm position and touch. The AdVAntage Artificial Arm will be adapted so that it can be controlled by multiple channel input from the recording electrodes and will be fitted with appropriate tactile and position sensors. These steps will expand the actuation ability of the AdVAntage Arm and add sensory feedback to the system. As a first step toward this goal, the types of sensations that can be elicited by stimulation of severed sensory fibers, the nature of control signals a person can generate on severed motor neurons, and the extent to which a subject can manipulate an artificial arm with these signals will be evaluated. This data will be used to design and construct a prototype Neuroprosthetic Arm.